Revista de Medicina e Saúde de Brasília
ARTIGO ORIGINAL
Effects of shiftwork on superoxide dismutase activity (SOD)
in Military Police Oficers
Efeitos da troca de turnos sobre a atividade da superóxido dismutase (SOD) em Policiais Militares
Carlos Kusano Bucalen Ferrari 1, Nubia Andrade Silva 2, Rosaline Rocha Lunardi 3,
Adenilda Cristina Honorio França 4, Eduardo Luzia França 4
Resumo
Objetivo: O objetivo deste estudo foi avaliar a atividade da superóxido dismutase (SOD) em
policiais militares de um município brasileiro. Métodos: foi desenvolvido um estudo
epidemiológico descritivo transversal com indivíduos do 2° batalhão da Polícia Militar em Mato
Grosso, Amazônia Legal, Brasil. Dois questionários validados foram utilizados para caracterizar a
população estudada e os problemas de sono, sendo o estresse avaliado segundo o inventário de
sintomas de estresse de Lipp (LSSI). Foi coletado o sangue e determinada a concentração sérica da
CuZn-SOD(E.C.1.15.1.1). Resultados: entre os policiais que trocam de turno, um terço tiveram
redução da atividade da SOD. Entretanto, a redução da atividade da SOD foi maior nos policiais
que não trocavam de turno (42%). Conclusões: a troca de turnos pode favorecer os fagócitos na resíntese de SOD que é um biomarcador da explosão respiratória componente essencial na defesa
frente a patógenos microbianos. A troca de turno teve efeitos positivos diminuindo o fardo do
estresse oxidativo.
Palavras chave: superóxido dismutase, estresse, troca de turno, sono, policial militar
Abstract
Objectives: this study aimed to assess the Superoxide dismutase (SOD) activity among police
officers from a Brazilian city. Methods: It was performed a descriptive cross-sectional
epidemiological study covering subjects from the 2nd Military Police battalion in Mato Grosso,
Legal Amazon, Brazil. Two validated questionnaires were used to charactherize the studied
population and sleeping disorders, and stress was evaluated by the Inventory of Stress Symptoms
for Adults by Lipp (LSSI). In 54 police officers blood were collected and serum CuZn4
1. Professor Adjunto de Saúde Coletiva do Instituto Latinoamericano de Ciências da Vida e Natureza (ILACVN),
Universidade Federal da Integração Latinoamericana (UNILA) e Orientador do Programa de Mestrado em
Imunologia e Parasitologia Básicas e Aplicadas, ICBS, Araguaia, Universidade Federal de Mato grosso (UFMT)
2. Mestranda em Imunologia e Parasitologia Básicas e Aplicadas (ICBS/UFMT)
3. Professora Assistente do ICBS/UFMT
4. Professor Adjunto do ICBS/UFMT
E-mail do primeiro autor: [email protected]
Recebido em 24/08/2013
Aceito, após revisão, em 05/03/2014
Ferrari CKB, Silva NA, Lunardi RR, Honorio França AC, França EL
Effects of shiftwork on superoxide dismutase activity (SOD)
SOD(E.C.1.15.1.1) levels were determined. Results: Among military officers who shiftwork, one
third had impaired SOD activity. However, the impaired SOD activity was higher among police
officers who did not shiftwork (42%). Conclusions: Shifwork can give phagocytes a chance to
resynthesize SOD which is a biomarker of the respiratory burst activity which is an essential key
against microbial pathogens. Shiftwork had positive effects decreasing the burden of oxidative
stress.
Key words: superoxide dismutase, stress, shiftwork, sleep, military
response to the alarm stage. The adaptation
Introduction
Stress includes a set of organic
phase could be chronicized causing fear,
reactions associated with physical, psychic,
nervousness, hair loss, changes in appetite
neuroendocrine, cardiovascular, immune and
and social isolation.4.
renal changes affecting the homeostasis as
Unable
adjustment
to
a
chronic
proposed by Hans Selye.1 Stress is considered
stressor causes exhaustion which compromise
a public health problem that raises costs for
homeostasis and is characterized by the onset
the individual, employer, and society.
of heart disease, gastrointestinal disorders,
Proposed by Selye in 1936, the general
and depression. In some cases it may lead to
adaptation syndrome has three basic stages:
shock,
alarm reaction, resistance, and exhaustion.2,3
subsequently death.4
Alarm phase is the initial conscious or
unconscious
reaction
to
a
stressor
multiple
organ
failure,
and
Lipp has characterized a fourth stage
of
stress,
between
the
resistance
phases,
being
called
and
characterized by physiologic changes to
exhaustion
near-
counteract the stressor. The sympathetic
exhaustion. This phase occurs when the
nervous stimulation results in substantial
individual becomes unable to adapt or resist
release cathecolamins, adrenocorticotrophin,
to a stressor, leading to the beginning of
cortisol, and antidiuretic hormone, leading to
disease pathogenesis.5,6
increased heart rate, blood pressure, sodium
Occupational stress can discharge
and water retention due to the stimulation of
organism energy affecting productivity and
renin-angiotensin-aldosterone system. Then,
satisfaction at the workplace.3,4,7 Stressful
during alarme phase people have headaches,
working has been associated with physical
abnormal
and mental fatigue, cognitive losses, high
blood
pressure,
irritability,
insomnia, and tachycardia.4
As an adaptation to the stressful
situations, resistance phase is a compensation
blood pressure, cardiovascular disorders,
behavioral
problems,
alcohol
and
drug
addiction, and psychosomatic symptoms.1,3,4
5
2238-5339 © Rev Med Saude Brasilia 2014; 3(1):4-11
Ferrari CKB, Silva NA, Lunardi RR, Honorio França AC, França EL
Effects of shiftwork on superoxide dismutase activity (SOD)
Military Police workers should face
(2nd Battalion / MT), Barra do Garças, Brazil.
conflicts, tensions, violence, poor health care
This population of police officers was
support, society criticism and other factors
characterized by male predominance (81%),
that usually result in job insatisfaction and
with aging ranging from 22 and 44 years old
distress.1,4,8,9
occupational
Shiftwork
is
(mean of 30 years), e.g., this is a relatively
another factor that disturbs police life
young population with 6 to 10 years of
resulting in a chronobiological disruption
service time, and 51% had incomplete college
associated with disorders, immunological
level. According to the Stress Symptoms
impairment, and sleep quality problems.10,11
Inventory for Adults (LSSI) 52% of the
Superoxide dismutase is a biomarker
sample was not stressed, but 48% of
of respiratory burst activity which is an
participants had clear stress symptoms. 70%
essential key for killing pathogenic bacteria,
of police women were found in some stage of
fungi,
protozoa.12-14
and
In
order
to
metabolize superoxide free radicals (O2-)
stress and 43% the policemen had also been
stressed as previously published.6,14
anions avoiding its excessive amounts the
Data were collected in the second
SOD enzyme converts superoxide anions to
battalion, on previously scheduled days
hydrogen peroxide (H2O2)11.
during the second semester of 2010.
Many studies with animal models of
both acute and chronic stress have been
Determination of CuZn-SOD concentration
showed impaired SOD levels among stressed
(CuZn-SODdE.C.1.15.1.1)
animals.15-19.
Police officers (54) were randomly
Then, the aim of this study was to
evaluate
symptoms
the
SOD
among
activity
police
and
officers
assigned in order to measure the serum SOD
stress
activity. SOD was measured in during service
who
entry and after service exit. The CuZn-SOD
shiftwork or not.
enzyme concentration was determined using
the nitroblue tetrazolium test (NBT; Sigma, St
Subjects and Methods
Louis, USA) and read at 560 nm with the
This study was an observational,
spectrophotometer.20 A 0.5 mL volume of
descriptive, and prospective investigation
serum samples was placed in test tubes, and
regarding SOD levels in military policemen
0.5 mL of standard hydroalcoholic solutions
and women who shift work or not.
(1:1 v/v) were prepared in other tubes. Both
The study population consisted of 54
samples of sera and the standard solutions
military police officers from the 2nd Military
were added to 0.5 mL of chloroform-ethanol
Police Battalion of the State of Mato Grosso
solution (1:1 ratio) followed by 0.5 mL of a
6
2238-5339 © Rev Med Saude Brasilia 2014; 3(1):4-11
Ferrari CKB, Silva NA, Lunardi RR, Honorio França AC, França EL
Effects of shiftwork on superoxide dismutase activity (SOD)
reactive
mixture
of
NBT
and
diaminoethanetetraacetic acid at a 1:1.5 ratio
comparing three or more independent samples
(v/v). After 2.0 mL of carbonate buffer plus
by BioStat2.0® software.
hydroxylamine were added, pH increased to
Following
10.2.24
The
tubes
Ethical
resolution No.196/10/1996, the study design
temperature for 15 minutes and underwent
was submitted and approved by the Research
spectrophotometrical reading. The reactive
Ethics Commitee of the “Júlio Müller
mixture reached zero values (for 3.5 mL). The
University
SOD was calculated by the following
University of Mato Grosso (protocol nº
relationship:
601/CEP-HUJM/09).
(Ab
at
Brazilian
room
SOD=
remained
the
standard_Ab
Hospital”
from
the
Federal
sample/Ab standard) X 100 = % reduction of
NBT/CuZn-SOD. The results were expressed
Results
Comparing the SOD values during job
in international units of CuZn-SOD.
Statistical analysis was performed
service entry and exit, the enzyme activity
using analysis of variance (ANOVA), and the
was strongly impaired among police with
nonparametric
test
for
administrative working but not among those
comparing two
independent
samples, and
directly working in street operations (Figure
nonparametric
Mann-Whitney
Kruskal-Wallis
test
for
1).
Figure 1. Superoxide dismutase mean values in Military Police officers (n-54) at entry and exit
from working according to type of function.
‫ ٭‬p=0,0048 in the exit according to service function
7
2238-5339 © Rev Med Saude Brasilia 2014; 3(1):4-11
Ferrari CKB, Silva NA, Lunardi RR, Honorio França AC, França EL
Effects of shiftwork on superoxide dismutase activity (SOD)
SOD levels were lower among police
Norwegian police staff studies which reported
workers who did not shifwork compared with
inadequate working schedules, lack of chief
that did (33% and 42%, respectively).
and organizational support, and bad working
conditions as the major risk factors for both
stress and psychiatric disorders32,33.
Discussion
Recent insights into the molecular
Although this study confirmed that
mechanisms of myocardial infarction revealed
both operational work and shifwork had less
that lower SOD levels were closely associated
impact on SOD levels, this study was limited
with increased risk of myocardial injury21,22.
by small sample size, absence of an adequate
In fact, decreased SOD levels have been
control group, its transversal design, and the
associated with hypertension, kidney damage,
absence of similar studies on the subject for
myocardial
adequate comparisons.
ischemic
injury,
pancreatic
damage, and stroke23-30. On contrary, SOD
overexpression rescue cell death in vital
organs (brain, kidney, heart) decreasing
diseases’ risk and its complications20-23,30.
This study is the first report regarding
decreasing
SOD
activity
among
Conclusions
Police women suffered from more
stress than policemen. Women officers had
predominantly the exhaustion stage of stress.
police
Since lacking of hobbies and leisure-time
officers. Police working is a chronic stressful
activities were strongly associated with stress
job. So, impairment of SOD activity could be
among police officers in France34, further
a plausible finding. Unexpectedly, police
studies are necessary to address the potential
workers who shiftwork experienced a lesser
benefit of preventive strategies as stated by
SOD decay compared with who did not
Cooper35, and more research is also relevant
shiftwork.
to evaluate the value of lifestyle factors such
Maintainance of adequate SOD levels
as physical activity, adequate nutrition and
is important to avoid infections which are
body composition, avoidance of smoking and
typical among in diabetic and chronic
alcoholic beverages, and availability of
granulomatous disease patients13,31, and in
leisure-time activities on the stress symptoms
cardiovascular and brain protection after
of police officers during shiftwork. This can
ischemic injury12.
explain why police officers who shiftwork
Our
results
could
be
plausible
considering data from a Switzerland and
had a lower impairment of SOD levels than
those who did not.
8
2238-5339 © Rev Med Saude Brasilia 2014; 3(1):4-11
Ferrari CKB, Silva NA, Lunardi RR, Honorio França AC, França EL
Effects of shiftwork on superoxide dismutase activity (SOD)
police force. Occup Med. 2003,
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